Loom dobby



c R. KRONOFF LOOM DOBBY Dec. 16, 1941.

Filed Sept. 7, 1940 I l l I I l TIL-1 I F F o M 9m T MR vm NN IE R f mATTORNEY "constitute the pivotal Patented Dec. 16, 1941 UNITED STAT LOOMDOBBY Clarence R. Kronofi, Worcester, Mass, assignor to Crompton &Knowles Loom Works, Worcester, Mass, a corporation of MassachusettsApplication September 7, 1940, Serial No.355,84'1

7 Claims.

This invention relates to improvements in loom dobbies and it is thegeneral object of the invention to provide a dobby employing many of thecurrently used parts of such a mechanism but wherein the lifting jackfor the harnesses is so mounted as to provide a considerably increasedwarp shed opening.

Loom dobby mechanisms customarily employ a pair ofcppositelyreciprocating lifter knives which cooperate with upper and lower sets ofhooks controlled by the pattern mechanism. The hooks are connected inpairs with the upper and lower ends of vertical dobby back levers whichin turn are pivoted to the harness lifting jacks. Heretofore the dobbyjacks have moved around a pivot below the lower set of hooks and thedobby back levers. In order to increase the angular. motion of the jackI have raised its fulcrum and constructed, the latter so that it willnot interfere with the back levers.

- The levers are swung outwardly from their normal position by the hooksattached to them and since either hook may be engaged by its knife thedobby back lever can assume either of two diagonal positions whichdefine a zone of op'erationof the levers. In order to achieve maximumlifting effect on the harnesses it is desirable to cause the jacks tomove about a center which is under the mid point between the two extremepositions of the pivotal connection betweenthe back lever and the jack.This point, however, lies within the aforesaid zone of operation of theback levers and it is an important object of my present invention toconstruct an arcuate pivotal support for the jacks the center of "whicheither lies within or is close to the vaforesaid range of operation. Thesupport is so placed that no part of it lies within said zone.

Itis a further object of my present invention to provide the pivotedsupport for the jacks with supporting ears or the like having provisionfor attachment withthe dobby frame at points lying substantially on thecenter of the arcuate bearing surface, the purpose of this constructionbeing to maintain the guide surface for the jacks in a correct positionwith respect to other centers of the dobby while permitting slightvariations in the actual'placing of the arcuate support, such as mightarise under manufacturing conditions.

It is a further object of my invention. to provide a transverse memberfor the dobby which will serve the dual purpose of supporting the lowerends of the dobby back levers and also support for the harness jacks.

It is another object ofmy invention to provide a support for the jackswhich will permit their removal without disturbing the support,

.the latter remaining permanently connected to the dobby and the jacksbeing so constructed that they can be removed one ata time while theothers are held in place by the support;

With these and other objects in view which will appear as thedescription proceeds, my invention residesin the combination andarrangement of parts hereinafter described and set forth. I v f In theaccompanying drawing, wherein two forms of my invention are'shown- Fig.l is a central vertical section through a dobby madeaccording to thepreferred form of my present invention, showing the dobby jack and itsoperating parts, in two different positions, V I

Fig. 2 is an end elevation of the dobby looking from the center of theloom in the direction of arrow 2, Fig. l, I

Fig. 3 is aperspective view of the arcuate pivotal support for theharness lifting jacks shown in Figs. 1 and 2,

Fig. 4 is an enlarged view similar a portion of Fig. 3 showing themodified form of the invention,

Fig. 5 is an end view of the arcuate support shown in Fig. 4, and I Fig.6 is a diagrammatic view showing the ,zone of operation of the dobbybacklevers with on one beat of the loom while the other knife has an inwardmotion to the right, and the motions of the two knives being reversed onthe next pick of the loom.

The knives: cooperate with top and bottom hooks l5 and I6, respectively,the positions of which with respect to-the knives is determined bypattern mechanism not shown. Each top hook is pivoted as at I! to adobby back lever I 8 the lower end of which is pivoted as at l9 to oneof the bottom hooks lfi. In this way each dobby back lever is-connectedto a pair of hooks, one to be actuated by the top knife and the other bythe bottom knife, according to the demands of the pattern being woven.The dobby has a top cross girt extending between and secured to theplates Ill to limit right hand motion of the tops of the levers l8. Thedobby is provided with a number of the levers I3 each of which can bemoved independently of the others on each pick of the loom.

At its mid point each lever |8 is pivoted as at 22 to a harness liftingjack J the upper end of which is provided with a series of notches 23one of which will ordinarily receive a harness lifter cord 24. It is acharacteristic feature of a dobby that the cord 24 will have exertedthereon a force directed to the right as indicated by arrow a in Fig. lby the weight of the harness frame not shown. This condition tends tomove the top of the jack to the right or toward the center of the loom,and also holds the top of levers 18 against top girt 29.

Fig. 6 shows diagrammatically the zone of operations of the levers |8.This zone Z is bounded on the right by the normal position of lever l8shown in full lines, Fig. 1, and at its top and bottom by the arcuatepaths traversed by upper and lower ends, respectively, of the lever.left boundary of the zone is determined by the two diagonal positionswhich the lever I8 can assume, one of which is shown in dotted lines,Fig. 1. The levers must. be free to move within this zone and anystructure extending into it would interfere with the operation of thedobby. The upper part U of the zone is due to movement of top hook I 5,while the lower part L is due to movement of the lower hook.

The parts of the dobby thus far described are of common construction,the hooks, knives, and dobby back levers being operated in the usualmanner and motion being imparted in the harness jacks through thepivotal connections 22.

In carrying my invention into effect I provide the lower end of each ofthe harness jacks J with an arcuate bearing surface which rests againstand slides along an arcuate pivotal support 3|. Support 3| in thepreferred form is provided at each end thereof with an ear 32, having aperforation 33 to receive a holding bolt 34 by which the support is heldin fixed position with respect to the frames III between whichitextends. In order to give the jack J maximum motion it should moveabout a center which is vertically below the mid point between the twoextreme positions which can be assumed by the pivotal connection 22. InFig. 1 this pivotal connection is shown in full lines in its rightextreme position and in dotted lines in its left extreme position. Themost favorable position for the axis of the jack would therefore be on avertical line which passes through the zone Z. Heretofore the axis forthe jacks has been located on the aforesaid vertical line but below thelower set of hooks |6, but in such a construction the ratio between thepower and working arms of the harness jack has been relatively low,thereby setting an objectionable limit to the height of the warp shed.

In order to increase the ratio between the power and working arms of thejack I raise its center toward pivot 22 to some such point as designatedby the a: mark C in Figs. 1 and 6. It is apparent, however, that thiscenter lies within the aforesaid zone of operation of levers l8 and itis for this reason that I form the support 3| as shown for instance inFigs. 1 and 3, with a parti-cylindrical surface the axis -of whichextends transversely of the dobby and harness jacks and passes throughthe point C. The arcuate The bearing surfaces 30 of the jacks slidevertically along the cylindrical surface 35 and cause the jacks to moveabout center C Without interfering in any way with movement of the hooksl6 and levers I8. The support 3| lies entirely outside the zone Z.

By the construction set forth in Fig. 1 the distance between the point Cand the axis 22 is less with respect to the distance between said pointC and the top notch 23 than formerly, with the result that the tops ofthe jacks can be given considerably more motion with resultant increasein the heights of the warp sheds.

In the preferred form of the invention the perforations 33 need notnecessarily bear any definite relation. with respect to the surface 35,but in the form of the invention shown in Figs. 4 and 5 I provide amodified support 40 having a parti-cylindrical surface 4| in allrespects similar to surface 35. Lateral ears 42 on support 40 haveperforations 43 the centers of which lie on the axis of the surface 4|,as indicated by arrow 1', Fig. 5. Each securing bolt 44 in the modifiedform therefore has its axis co-incident with the center of the surface4| around which the jacks move and any slight mis-adjustment of thesupport 43 will not alter the center of the jacks.

It has heretofore been customary to provide the lower part of the dobbywith a girl: similar to that shown at 20 for the top of the dobby. Afurther feature ofmy present invention is to provide the pivotal support3| with a surface 31 along which the bottom right edge of levers |8 mayslide when the top hook is moved outwardly or to the left by the upperknife. The modified support 40 may be provided with a guide surface 45similar in function tothe surface 3-! of the preferred form of thesupport. In this way I combine a guide for the lower partof the leversIS with an arcuate support for the harness jacks, causing supports 3|and 40 each to perform two functions heretofore accomplished by twoseparate parts.

In order to prevent the jacks from becoming displaced during assembly,and to permit their removal one by one, I provide a guide pin 38extending between the plates 10 for engagement with an arcuate surface39 on the inner edge of the jack, this surface being concentric with theax-isC.

Prior to placing the jacks in the dobby the top and bottom cross girts30 and 31, andalso the rod 38 will be placed in position. The jacks willthen be moved to the extreme left hand position indicated by the shortdotted line b in Fig. 1 against the right hand side of the top .girt 20with the arcuate bearing close to the bottom support 3|. In thisposition the bottom of a narrow foot at the lower end of the jack lyingbetween the concentric surfaces .30 and'39 will be able to slide downbetween rod 38 and surface 30 to permit a right hand angular motion ofthe jack with the surface 30 sliding on the surface 35 around axis C asa center. Under the conditions of assembly the jacks will not beconnected to the harness cords 24 nor will their right hand positions bedetermined by the levers 13, since the latter are not connected to thejacks until after assembly. It is for this reason that I provide theheel on the jack which extends over the rod 38 to serve as a support tohold the jacks in place in a position approximating that shown in fulllines in Fig. 1. After all the jacks are inserted into the dobby, theyare moved to the left one by one and the levers l8 connected to them,after which the jacks will again move to the right by their weight butwill now be limited in their motion byengagement of the top and bottomof lever 18 with the corresponding cross girts and the heel 80 will beslightly above the rod 38. If it should be necessaryto remove one of thejacks it will be swung to the extreme left handpositiomthe lever l8disconnected, and then raised while rod 38 is still in position tosupport the other jacks. It will be noted from Fig. 1 that the rod 38 islocated close to thebottom of foot 50 when the jack is in its left handposition and it is because of this location of pin38 that the jack canbe removed. Foot 50 is long enough to provide adequate bearing contactwith surface 30 when the jack is in the dotted line position shown inFig. 1. I have found that the proper length of wearing surface can beobtainedif the parts are so proportioned that'a line drawn between thebottom 5| of surface 30 and the axis 22 lies to the left, or on thelever side of the upper end 52 of the bearing surface 30. When the partsare in the full line position shown in Fig. 1, point 52 should be asnear as convenient to the lever I8 to insure maximum bearing surfacebetween the jack and the surface 35, but when lever I8 is moved to thedotted line position it will move a considerable distance away frompoint 52. I find however that when the top hook I5 is moved to the leftto move the lever through the range of movements indicated at U in Fig.6, no objectionable engagement will occur between the lever and thepoint 52 of the jack bearing even though part of the jack moves into theaforesaid zone'of operation, provided there is a slight clearance at thestart of motion of the lever. This clearance can beprovided by havingpoint 52 located to the right of a line joining point 5| and axis 22.Interference is avoided also due to the fact that the lower end of leverI8 is not far removed from the center C and turns at approximately thesame rate as does the jack. This last named relation permits the use ofrelatively long bearingsurfaces on the jack and bottom girt and growsout of the fact that the lower end of the lever is in substantialalignment with the arcuate bearing surface on the jack. Ample bearingsurface is provided despite the fact that the arcuate contact isconsiderably less than 180.

In operation, the reciprocating knives will pick up one or the other ofthe hooks and the lever l8 will be moved from its normally verticalposition to a diagonal position. If the bottom hook is pulled outwardlyor to the left the center 22 will move from its right extreme positionto the left extreme position and cause the guide surface 30 of the jackto slide upwardly in a curved path over the arcuate surface 35 and causemovement of the top of the jack around the center C. At the same timethe top of lever l8 will slide downwardly a short distance along thecross girt 20. Should the upper hook be pulled outwardly the top oflever l8 will move to the left and center 22 will again assume its leftextreme position and cause rocking of the jack as already described, butin this instance the lower end of lever l8 will slide upwardly along thesurface 31 of the arcuate support. Upon return motion of the lever l8 toits normal position, regardless of which hook had previously moved tothe left, the surface 30 of the jack will slide downwardly in a curvedpath along the arcuate surface 35. A similar operation will occur whenthe modified form of arcuate support as shown in Figs. 4 and 5 is used.

From the foregoing it will be seen that I have provided a simple meansfor giving increased motion tothe harness lifting jack-of a dobby thegreater part of which is constructed of levers and hooksofcommonconstruction. It will further be seenthat the jack moves around animaginary center which lies within the zone of operation of theleverslli. hence the latter are free to move without interference on the partof the supports 3lor 40.; In 'themodified form of the invention 'thesecuring bolts 44 are co-axial with the cylindrical surface! I so thatslight misplacements of "the support All willnot alter the location ofthe center aboutwhich the jacks J oscillate. It will also be seen thatthe arcuate guide, for the jacks provides a support for the lower end ofthe levers 18. The fact that the upper end of the jacks are constantlyacted upon by the forces acting in the direction of arrow a, Fig. 1,'serves to hold the arcuate guide surfaces 30 against the surfaces 35 or,depending upon whetherthe preferred or modified form of arcuate supportis employed,and the pin'38 serves to hold the jacks in position whilethey are being connected-to their respective harness frames.

Furthermoresince the lower end of the lever I8 is normally close to thearcuate bearing surface of the corresponding jack, the sliding curvedsurfaces of both the jack and the cross girt can be made relativelylongso that pressure between the jack and its support is comparatively low.As a more detailed advantage of the inventionthe jack is so constructedthat a line joining the low; est point'of the surface 30 with the axisof lever 18 passestoone side of point 52, the latter being on the sameside of this .line as is the curved bearing 38 and the body of the jack.I

Having thus described my invention it; will" be seen that changes andmodifications may be made therein by those skilled in the art withoutdee partingffrom'the spirit and scope of theinvention' and I do not wishto be limited to the details herein disclosed, but, what I claim is: t

l. Ina loom dobby'havinga pair of spaced side plate frames between whichare located a series of levers each of which has a dobby, hook'pivotedto the top thereof and another dobby hook pivoted to the bottom thereof;the dobby having reciprocating knives supported by and movable withrespect to the side frames to engage the hooks and move the lattertogether with the levers through a given zone of operation, a series ofharness lifting jacks each of which is pivoted to one of the aforesaidlevers, means on the lower end of each jack defining an arcuate bearingsurface, a support for the jacks extending between the side frames andhaving an arcuate bearing surface to engage and have sliding relationwith respect to the bearing surfaces of the harness jacks, said supportbeing located outside the zone of operations of the levers and hooks andsaid bearing surfaces of the jacks and support being concentric with acenter located within said zone of operations of the levers and hooks,and means to secure the support to the side frames along the center ofsaid bearing surfaces of the jacks and the support, whereby slightvariations in the location of the support will maintain the arcuatesurface thereof concentric with the aforesaid center for all positionsof the support around said securing means.

2. In a loom dobby having a pair of spaced side plates between which arelocated a series of levers each of which has a dobby hook pivoted to thetop thereof and another dobby hook pivoted to the bottom thereof, thedobby having reciprocating knives supported by and movable with respectt the side plat s o ngage the hooks and move the latter to ether withthe levers through a iven zone of operation a series of harness liftingjacks each of which is pivoted to one of the aforesaid levers, a supp rtfor the lower ends of the harness jacks extending between said sideplates, means on said jacks and said support defining mutually engagingarcuate bearing surfaces having their center located within said zone ofoperation of the levers and hooks, and bolts having their axes locatedalong said center to secure the support to the side plates of the dobby,whereby said support is capable of assuming a plurality of positionswithrespect to said side plates around said bolts While at the same timemaintaining the arcuate bearing surfaces of said support concentric withsaid center.

3. In a loom dobby having spaced side plates between which are located aplurality of levers each of which is p ovided with a pair o hooks to beactuated by reciprocating knives mounted on and sliding relatively tothe side plates, the dobby having a top cross girt to engage the upperpart of each lever and having also a harness lifter jack pivoted to eachlever, the upper parts of the jacks being acted upon by a constantlyexertediorce to move in a direction away from said cross girt and thelatter being between the levers and the jacks, a bottom cross girtlocated between the lower ends of the levers and the jacks placed forengagement with the lower parts of the levers, the jacks tending to holdsaid levers against the top and bottom girts, the bottom girt beingformed with an arcuate surface, and the lower end of each jack beingprovided. with an arcuate bearing to have sliding contact with thearcuate surface on the bottom girt.

4. In a 100m harness controlling me hani m having a harness jack movablethrough a ven range of angular motion, a fixed bearing having an arcuatebearing surface, a slide bearing formed on the lower end of the jack andhaving an arcuate surface to slide over said fixed bearing when the jackmoves through said range of angular motion, a guide on said jack havinga guiding surface formed as an are substantially concentric with saidslide bearing, and a retaining means lying close to said guide andspaced above the bottom of said guidi g surface when the jack is at oneextreme of said range of angular moti n nd l a ed lo e to the bottom ofsaid guidin surfa when sa d jack s in the other extreme of its range ofangul r motion- 5, In a loom dob'oy having a dobby back lever and hooksconnected thereto to engage reciprocating knives to move a harness jackconnected to the lever through a given range of angu ar motion, abearing fixed to the dobby and having an arcuate bearing surface, afootformed on the lower end of the Ja k and having an rcuate sliding bearingsurface on one side thereof ior en a ement with said fixed bearing andhaving the other side thereof substantially concentric with the slidebearing, said foot to slide 0Y3! the fixed bearing through the aforesaidrange of a gular motion, and a retainer adja ent to. said other side ofthe root and located a substantial distance above the bottom of saidfoot when the lack is in one ex reme of said ran e of angu ar motion andlocated near the bottom Of. said 10 whenthe jack is in the other extremeof said range of angular motion.

'6. A combined dobby cross girt and harness jack bearing fora dobbyhaving spaced side plates and operating with a dobby hack lever pivotedto a harness jack which has an arcuate bearing surface, said combinedcross girt and jack bearing having a surface on one side't here= of forengagement with the lever and an arcuate surface on the other sid h e ffor slidin engagement with the bearing of the jacks, and ears formed onthe ends of the cross girt provided with holes to receive attachingmeans supported by the side plates, said holes having their axesconcentric with the arcuate suriace on said other sid of th combined c os girt and i a k b ar n 7, A harness jack for a dobby having a jacksupport formed with an arcuate bearing sure face and a supporting pinspaced from said are cuate bearing surface, said jack having a foot atthe lower end t reof l ca ed e n tw substantially concentric surfacesone of which is formed for sliding engagement with the arouate surface othe jack s pport and thc'o h r o which is located for en agement withsaid pin, said foot throu hout its length having a width notsubstantially greater than the distance be tween said pin and saidarcuate surface .on the jack support,

CLARENCE R. KRONOFF.

